Should your next Symfony application be headless, or should it remain a monolith?

In e-commerce, this is often one of the first architectural questions teams need to answer. Clients want modern, dynamic, responsive user experiences. Developers want maintainable systems. Businesses want fast delivery, good SEO, reasonable costs, and the ability to evolve the product over time.

For a long time, the discussion has often been presented as a binary choice: either we build a traditional server-rendered application, or we move to a fully headless architecture with a separate frontend application. Both options have strong arguments. Both also come with hidden costs.

In this talk, we will compare both approaches from a practical Symfony perspective. We will look at SEO, performance, responsiveness, frontend flexibility, team workflow, deployment complexity, maintaining multiple repositories, and the long-term cost of ownership.

But the main goal of this talk is not to declare a single winner.

Instead, we will ask a more useful question: do Symfony teams still have to choose between a classic monolith and a fully headless architecture?

Thanks to Symfony UX, Live Components, Twig Components, and the ability to use React or Vue components directly inside Twig, Symfony gives us a powerful middle ground. We can keep the productivity, simplicity, and SEO advantages of a traditional Symfony application, while progressively introducing dynamic, interactive frontend experiences exactly where they bring real value.

I will share how we successfully implemented this approach in Sylius, what we learned from the e-commerce world, and how these lessons can help Symfony teams build modern, dynamic applications without immediately turning every project into a fully headless architecture.

Attendees will leave with a practical framework for deciding when to stay with a monolith, when to go headless, and when a hybrid Symfony architecture can give them the best of both worlds.